Method for clay stabilization with quaternary amines

ABSTRACT

A method of treating a clay-containing subterranean formation with an aqueous fluid is disclosed. The method features the use of quaternary ammonium compounds as additives to control formation damage caused by contacting the formation with the aqueous fluid.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of my prior copending applicationSer. No. 07/657,700 filed Feb. 28, 1991, now U.S. Pat. No. 5,097,904.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method of and a fluid additive for treatingsubterranean formations containing clays. The additive finds particularuse in aqueous stimulation fluids such as fracturing fluids.

2. Prior Art

The production of oil and gas from subterranean formations which containclays and other fines is often impeded by the unstable nature of thesematerials. Clays and fines when in an undisturbed condition are stableand cause no obstruction to the flow of hydrocarbons through theformation. However, when these materials are disturbed by contact withan aqueous fluid that is foreign to the formation, the clays can swelland the fines can migrate through the capillary flow channels in theformation resulting in a reduction of formation permeability, which issometimes referred to herein as formation damage.

Attempts to diminish the damaging effects of introduced aqueous fluidsupon subterranean formations have included the conversion of claycontained in the formations from a swelling form to a less swellingform. This method of control has featured the addition of various saltsto the aqueous fluids utilized in the treatment of subterraneanformations. Inorganic salts such as potassium chloride, calciumchloride, and ammonium chloride have been dissolved in an aqueous fluidutilized to treat a formation. The solubilized salts enter into a cationexchange with the charged particles comprising the clays. While thesesalts often do diminish the reduction of formation permeability, theycan be detrimental to the performance of other constituents of thetreatment fluid. For example, the salts which are typically admixed withthe aqueous fluid before admixture of any viscosifying or gelling agentsto the aqueous fluid, may have a detrimental effect upon the viscosityyield by the gelling agent upon hydration in the aqueous fluid.

Furthermore, such salts, and particularly those containing chlorideions, are finding environmental objections and are therefore preferablyto be avoided. Accordingly, it would be desirable to provide anenvironmentally acceptable method and additive by which a subterraneanformation can be protected from the damaging effects of foreign aqueousfluids wherein the treating fluid used can be prepared simply andwithout detrimental effects to fluid constituents.

SUMMARY OF THE INVENTION

By this invention there is provided a method of treating a subterraneanclay-containing formation comprising contacting said formation with anaqueous fluid whereby damage to the formation caused by contact with theaqueous fluid is reduced or substantially eliminated. The aqueous fluidcan be a fluid containing a gelling agent which increases the viscosityof the fluid. The aqueous fluid can have a range of pH values extendingfrom acidic to basic. The formation treatment can be for the purpose ofenhancing the recovery of fluids from the formation such as by afracture stimulation treatment and/or an acid stimulation treatment.

A formation treatment performed for the purpose of enhancing therecovery of fluids, such as oil or gas, from the formation at leastpartially depends for success upon increasing the permeability of theformation. If the treating fluid itself tends to damage the formation bydecreasing the permeability thereof then steps must be taken to reduceor substantially eliminate such damage.

The problem of reducing or substantially eliminating the damaging effectof an aqueous fluid upon a clay-containing subterranean formation wasspecifically addressed in U.S. Pat. No. 4,842,073 to Himes, et al., whodisclose therein the addition to the aqueous fluid of certain quaternaryammonium compounds to stabilize the formation and to thus reduce or tosubstantially eliminate damage to the formation caused by the aqueousfluid.

The quaternary ammonium compounds disclosed by Himes, et al., andreferred to as formation control additives, consist of specifiedquaternary ammonium cations and, principally, halide as well as otherdisclosed inorganic anions. These formation control additives act toreduce or eliminate the decrease in the permeability of clay-containingformations contacted by an aqueous fluid. The phrase, formation damage,and similar such descriptions utilized by Himes, et al., and also asused in this invention, refer to the decrease in the permeability of aclay-containing formation caused by contact thereof with an aqueousfluid.

This invention provides formation control additives useful in aqueousfluids in amounts effective to prevent damage to clay-containingformations contacted by the aqueous fluids. The formation controladditives of this invention, being liquid phase compounds, are easilyhandled by conventional equipment and are readily soluble in usefulquantities in aqueous fluids used in conventional formation treating andstimulation procedures. The formation control additives are not known tointerfere with the function of other additives known to be useful inaqueous treating fluids, for example, gelling agents.

In addition to the above benefits, and in another aspect of thisinvention, it is believed that certain of the fluid additives employedherein can be used without adverse affect upon animal, soil and waterresources. These certain fluid additives are quaternary ammoniumcarboxylates and thus biodegrade to environmentally acceptable endproducts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic schematic illustration of the test apparatusutilized in the Examples.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Hydraulic fracturing is well known as a method for stimulating the flowof fluids, such as oil or gas, from a subterranean formation. Accordingto the method, a subterranean formation is contacted by a fluid at aflow rate and pressure at least sufficient to create or extend afracture into a desired portion of the formation. The fracturing fluidnormally contains a proppant which is transported into the fracture toprevent the fracture from completely closing once pressure is released.Various fluids have been utilized in hydraulic fracturing, however, mostfluids in current use are aqueous-based liquids.

A fracturing fluid can be prepared by admixing a quantity of asolvatable polysaccharide gelling agent with an aqueous liquid.Solvatable polysaccharides include galactomannan gums, glucomannan gums,cellulose derivatives and the like. The fracturing fluid may alsoinclude a crosslinking agent for the gelling agent as well as otheradditives. For example, the fluid can contain bactericides, gelbreakers, iron control agents, foaming agents such as surfactants, gasesor liquified gases, stabilizers and the like. The preparation offracturing fluids and the use of various additives therein are wellknown to individuals of ordinary skill in the art. The selection of theparticular fracturing fluid constituents such as the gelling agent,crosslinking agent, breaker, stabilizer and the like is not critical tothe successful operation of the present invention.

Aqueous fracturing fluids can also include a formation stabilizationadditive. The formation stabilization additives utilized have been watersoluble inorganic salts such as potassium chloride, ammonium chloride,sodium chloride and calcium chloride. As previously indicated thesesalts can be difficult to use and can have detrimental effects uponcertain properties of the gelled fluid such as reducing the viscosityproduced by a gelling agent in the aqueous fluid in comparison to theviscosity produced by the gelling agent in fresh water. These compoundshave been utilized, however, because of the ion-exchange properties ofthe clays present in the subterranean formations to be treated and theability of these chemicals to provide some degree of formationstabilization through ion-exchange with the clays.

Included among the clays which can be effectively treated in accordancewith the present invention are clay minerals of the montmorillonite(smectite) group such as montmorillonite, saponite, nontronite,hectorite, and sauconite; the kaolin group such as kaolinite, nacrite,dickite, and halloysite; the hydrousmica group such as hydrobiotite,glauconite, illite and bramallite; the chlorite group such as chloriteand chamosite; clay minerals not belonging to the above groups such asvermiculite, attapulgite, and sepiolite, and mixed-layer varieties ofthe above minerals and groups. The clay content of the formations can becomprised substantially of a single species of clay mineral, or ofseveral species, including the mixed-layer types of clay. Clay mineralscommonly encountered in subterranean formations which are subject to thedifficulties herein noted and which can be treated effectively inaccordance with the present invention are those selected from themontmorillonite group, hydrousmica group, chlorite group, kaolin groupand mixed layer types. It will be understood that the clay formationstreated in accordance with the invention need not be composed entirelyof clay but may contain other mineral components associated therewith.

Clays can swell, disperse, disintegrate or otherwise become disrupted inthe presence of foreign aqueous fluids. A clay which swells is notlimited to expanding lattice-type clays but includes all those clayswhich can increase in bulk volume with or without dispersing,disintegrating or otherwise becoming disrupted when placed in contactwith foreign aqueous solutions such as water, and certain brines.Certain clays can also disperse, disintegrate or otherwise becomedisrupted without swelling in the presence of foreign aqueous solutionssuch as water, certain brines, and emulsions containing water or certainbrines. Some clays, in the presence of foreign aqueous solutions, willexpand and be disrupted to the extent that they become unconsolidatedand produce particles which migrate into a borehole. Formations whichconsist largely of clay upon absorbing water in a confined space candevelop pressures on the order of several thousands of pounds per squareinch.

The clay materials defined above occur as minute, plate-like, tube-likeand/or fiber-like particles having an extremely large surface area ascompared to an equivalent quantity of a granular material such as sand.This combination of small size and large surface area results in a highsurface energy with attendant unusual surface properties and extremeaffinity for surface-active agents. The structure of some of theseclays, for example, montmorillonite, can be pictured as a stack ofsheet-like three-layer lattice units which are weakly bonded to eachother and which are expanded in the "c" crystallographic direction bywater or other substances which can penetrate between the sheets andseparate them. The cation exchange capacity of Montmorillonite is in therange of from about 90 to 130 milliequivalents per 100 grams of pureclay; that of illite is in the range of from about 20 to 40milliequivalents; and that of kaolinite is in the range of from about 5to 15 milliequivalents.

Clays include cations which occupy base-exchange positions or sites. A"base-exchange position or site" is defined as an area on the surface ofa clay crystal which has associated with it an exchangeable cation.Cations generally found on a base-exchange position or site includesodium, potassium, calcium, magnesium, iron and hydrogen as well asother types. These cations are believed to be held on the clay surfaceby ionic forces.

Cations occupying the base-exchange sites on clay can be thoseoriginally present thereon or those placed thereon by liquids placed incontact therewith. Accordingly, the nature and concentration of ions inan aqueous liquid placed in contact with the clay can determine thecations occupying the base exchange sites. In most oil well formationsthe connate water associated therewith contain sodium as the predominatecation, with calcium, magnesium and other cations present in muchsmaller quantities. Since base-exchange positions on clay are occupiedby cations, in many cases the cation will be sodium when connate watersare sodium containing. Unfortunately, however, as for example in thecase of the sodium form of montmorillonite, these clay minerals swell inthe presence of foreign water or certain brines and can, in someinstances, exert pressures up to thousands of pounds per square inch.Thus, dependent upon the nature and amount of water absorbed, the claycan change to a rigid paste or a gelatinous mass, or if sufficient wateris present, the clay can disperse completely into the aqueous phase.

The swelling or dispersion of clays can significantly reduce thepermeability of a formation. The use of salts as formation controladditives has not eliminated formation damage as a result ofpermeability reduction, but can reduce or minimize such damage.

The formation control additives employed in aqueous treating fluids usedin the treating methods of this invention are certain quaternaryammonium compounds having inorganic anions and carboxylate anions. Thosequaternary ammonium compounds having carboxylate anions being entirelyorganic in nature are biodegradable and thus enjoy a greaterenvironmental acceptance than those which do not have carboxylateanions.

The additives useful herein are selected from compounds of the generalformulas: ##STR1## wherein A represents the group ##STR2## B representsthe group ##STR3## C represents the group ##STR4## D represents thegroup ##STR5## E represents the group ##STR6## and F represents ##STR7##and further wherein: R₁ is selected from the groups, --CH₂ COOH, --CH₂CH₂ OH, --CH₂ CH₂ CH₂ OH and --CH₂ CHOHCH₃ ;

R₂ is selected from the groups, --CH₂ CH₂ --, --CH₂ CHOHCH₂ --, --CH₂CH₂ CH₂ --, --CH₂ CH₂ CH₂ CH₂ --, and --CH₂ CH₂ OCH₂ CH₂ --;

R₃ is selected from the groups, ##STR8## R₄ is independently hydrogenand the group --(CH₂)_(n) CH₃ wherein n has a value in the range of 0 to5 and at least one of said R₄ substituents is said --(CH₂)_(n) CH₃group;

Z is an anion selected from halides, nitrates, nitrites, sulfites,sulfates and carboxylates; and

Y is an anion selected from carboxylates.

The halide can be fluoride, chloride, bromide or iodide.

The carboxylates through to be useful as anions herein are believed tobe any water soluble carboxylate, examples of which include:

formate, HCOO⁻ ;

acetate, CH₃ COO⁻ ;

hydroxyacetate, HOCH₂ COO⁻ ;

lactate, CH₃ CHOHCOO⁻ ;

citrate, ⁻ OOCCH₂ COH(COO⁻)CH₂ COO⁻ ; and

benzoate, C₆ H₅ COO⁻ ;

Numerical coefficients are not shown on the above formulas; however, itis recognized that to maintain electrical neutrality, sufficient cationportions and/or sufficient anion portions are present to properlybalance the equations of the formulas. Thus, for example, a specificquaternary ammonium citrate may have three cation portions and one anionportion, but would be represented herein by the general formula AR₁ Z;also a specific diquaternary ammonium halide may have one cation portionand two anion portions but would be represented herein by the generalformula AR₂ AZ. Specific compounds found useful herein which are withinthe scope of the above formulas are:

2-Hydroxy-N,N-Bis(2-Hydroxy Ethyl)-N-Methyl Ethanaminium Chloride

N,N,N-Trimethyl Methanaminium Acetate

2-Hydroxy-N,N,N-Trimethyl Ethanaminium Citrate

N-Methyl Alkyl Pyridinium Chloride

2-Hydroxy-N,N,N-Trimethyl Ethanaminium Chloride

2-Hydroxy-N,N,N-Trimethyl-l Propanaminium Acetate

2-Hydroxy-N,N,N-Trimethyl Ethanaminium Formate

2-Hydroxy-N,N,N-Trimethyl-I Propanaminium Formate

1-Carboxy-N,N,N-Trimethyl Methanaminium Chloride

1,3-Bis(Trimethanaminium), 2-Propanol Dichloride

2-Hydroxy-N,N,N-Trimethyl Ethanaminium Acetate

1,2-Bis(Trimethanaminium) Ethane Dichloride

2-Hydroxy-N-(2-Hydroxy Ethyl)-N,N-Dimethyl Ethanaminium Chloride

The formation control additives of this invention, which are quaternaryammonium compounds, are admixed with aqueous treating fluids in anamount effective to substantially stabilize a claycontaining formationagainst permeability reduction as a result of contact between theformation and the fluid. An effective amount of the formation controladditive is believed to be about 0.05 percent additive by weight of theaqueous fluid. The formation control additive is preferably present inan amount in the range of from about 0.1 to about 5 more preferably 0.1to about 0.6 and still more preferably 0.15 to about 0.5 percentadditive by weight of the aqueous fluid.

The formation control additive can be admixed with the aqueous fluid,such as an aqueous fracturing fluid, at any time prior to contact of thefluid with the subterranean formation. The formation control additivesof this invention are readily available as liquid solutions, thereforethey readily admix with the constituents of an aqueous fracturing fluidboth prior to and subsequent to hydration of the gelling agent. The useof the formation control additives is particularly advantageous instimulation treatments performed with liquid gel concentrates such asfor example those described in U.S. Pat. Nos. 4,312,675; 4,435,217;3,894,880; 3,894,879; and 4,466,890.

The formation control additive is effective in treating a subterraneanformation when transported in an aqueous carrier fluid having either anacid, alkaline or neutral pH in the range of from about 1 to 11 withoutany significant detrimental effect upon the additive.

The formation control additive may be admixed with the constituents ofan aqueous liquid gel concentrate during its preparation whereupon thegel remains storage stable. The additive may be admixed with the gelconcentrate when the gelled fluid is prepared by introduction of thecontrol additive into a mixing vessel or blender together with otherfluid additives. The formation control additives of the presentinvention do not exhibit mixing problems associated with previously usedsalts and do not appear to have any significant detrimental effect uponthe hydration or ultimate yield of the gelling agent utilized to preparea gelled fluid such as a fracturing fluid.

The following examples are presented to illustrate the effectiveness ofthe formation control additives in the prevention of substantialpermeability reduction upon contact of an aqueous fluid with aclay-containing formation. The examples are not to be considered aslimitations upon the scope of the present invention but are presentedfor illustration only. All quantities, proportions and percentages areby weight and all tests were performed at room temperature unlessotherwise indicated.

EXAMPLES

Referring now to FIG. 1, there is illustrated, in schematic format, adiagram of equipment utilized in the Examples. Thus, a core sample to betested is mounted in a Hassler sleeve test cell, 1, having one endthereof designated as the formation side, 3, and the other end thereofdesignated as the wellbore side, 5. The direction of fluid flowingthrough cell 1 from side 3 to side 5 is referred to as the productiondirection, and the direction of fluid flowing through cell I from side 5to side 3 is referred to as the treatment direction.

The equipment includes a 3-way, high pressure ball valve, 7, and a3-way, high pressure ball valve, 9. Thus, by appropriate manipulation ofball valves 7 and 9 fluids can be directed through cell 1 via lines 11,13 and 15 in either the production direction or the treatment direction.

The pressure difference across cell 1 between formation side 3 andwellbore side 5 is measured by differential pressure transducer, 17,mounted between lines 19 and 21 wherein line 19 exhibits the pressure offluid entering cell 1 via lines 11 or 13 and line 21 exhibits thepressure of fluid exiting cell 1 via lines 13 or 15.

Transducer 17 is connected to a computer, not shown, that contains andstores permeability data pertaining to the core being tested and fluidvolume data pertaining to the volume of fluid passing through the corebeing tested.

All fluid flowing through the equipment system shown in FIG. 1 exits thesystem via lines 23, back pressure regulator 25 and line 27.

All fluid entering cell 1 originates from one of three vessels 29, 31 or33 via lines 35 and selection valve 37. Each of vessels 29, 31 and 33can be isolated from the system by isolation valves 39 and 41, 43 and45, and 47 and 49 respectively. By appropriate manipulation of valves37, 39, 41, 43, 45, 47 and 49 fluid can be caused, as described below,to flow from one of vessels 29, 31 or 33 and into and through cell I ineither the production direction or the treatment direction (as definedabove).

In addition to the above, all fluids entering the system are passedthrough a 0.5 micron filter (not shown) prior to entering cell 1.

Fluids entering the system must overcome resistance to flow offered byback pressure generated by regulator 25 as well as resistance offered bythe core itself in cell 1 and resistance offered by tubing and valves.This total resistance is overcome by applying pressure to vessels 29, 31and 33 via line 51 which is connected to a constant displacement highpressure pump (not shown). Light mineral oil is moved by the pump intothe tops of vessels 29, 31 and 33 to displace therefrom the fluidcontained therein and into and through cell 1. In the tests, backpressure regulator 25 maintains a constant pressure of 300 psig in lines23 on the discharge side of cell 1.

As mentioned above fluid to be passed through cell 1 originates fromvessels 29, 31 and 33. Vessel 29 contains deionized water; vessel 31contains a 5 percent solution of sodium chloride and vessel 33 containsthe treatment fluid.

In operation of the equipment the initial permeability, K_(i), of thecore maintained in cell 1 is obtained by flowing the sodium chloridesolution from vessel 31 through the core in the production direction.The length of the core in cell 1 is selected as being the average depthof invasion of fluids into a formation during a fracturing treatment.

Upon determination of initial permeability, K_(i), the pump rate isreduced to zero and the equipment valves manipulated to permit fluidflow through the core in cell 1 in the treatment direction at which timeone pore volume (pv) of treatment fluid from vessel 33 is caused to bepassed through cell I in the treatment direction. Thereafter, the pumprate is again reduced to zero and the equipment valves again manipulatedto permit fluid flow through the core in cell I in the productiondirection at which time the sodium chloride solution from vessel 31 isagain passed through the core to obtain final permeability, K. Anychange between initial permeability, K_(i), and final permeability, K,is caused by the treatment fluid. Core damage is indicated where K_(i)is greater than K. Another indication of permeability change isindicated by the ratio, K/K_(i), of final permeability to initialpermeability. Where the ratio is less than one, permeability has beenreduced (i.e. damage); where the ratio is one or more permeability hasbeen preserved or improved (i.e. no damage).

Various different treatment fluids were utilized in accordance with theabove test procedure. The test results obtained for each treatment fluidare provided in terms of the ratio, K/K_(i), reported as a percent; thatis, final core permeability is expressed as a percent of initial corepermeability.

It is believed that the test procedure described does simulate theformation damage that could result from the introduction of an aqueousfluid into a subterranean formation.

After final permeability, K, is obtained, fresh water from vessel 29 isthen passed through cell 1 in the production direction to obtain waterpermeability, K_(w). If the ratio K_(w) /K_(i) is less than the ratioK/K_(i), then the core tested is considered to be water sensitive and itis concluded that the test conducted is a valid test of the effect ofthe particular treating fluid on a water sensitive sample.

In every test reported herein, the water permeability test confirmedthat all core samples tested were water sensitive.

EXAMPLE 1

This invention is related to the invention disclosed and claimed in U.S.Pat. No. 4,842,073 issued Jun. 27, 1989, to Himes, et al., whichdiscloses and claims treating fluids used for the same purpose utilizedherein but which contain formation stabilization additives which arechemically distinct from the ones disclosed and claimed herein. Forpurposes of comparison only results obtained by Himes, et al. usingsubstantially the same test method described above and reported in TableII of U.S. Pat. No. 4,842,073 are also reported in Table I below.

                                      TABLE I                                     __________________________________________________________________________    OHIO SANDSTONE CORE                                                           Chemical Compound                                                                         Abbreviation                                                                         Structure             % Solution                                                                          K/K.sub.i,                     __________________________________________________________________________                                                   %                              Deionized Water                                                                           DI     --                    --    72                             Potassium   KCl    --                    0.1   74                             Chloride Solution                                                             Tetramethylammonium Halide                                                                TMAC                                                                                  ##STR9##             0.1   109                            Tetrabutylammonium Halide                                                                 TBAC                                                                                  ##STR10##            0.5   93                             N,N,N-Trimethylphenyl- ammonium Halide                                                    TMAI                                                                                  ##STR11##            0.5   80                             N-Methylpyridinium Halide                                                                 MEPY                                                                                  ##STR12##            0.5   100                            N,N-Dimethylmor- pholinium Halide                                                         DMMI                                                                                  ##STR13##            0.5   96                             Methyl Quaternary Ammonium Salt of 2 Mole Oligomer of Epihalohydrin                       EPIQ                                                                                  ##STR14##            0.5   94                             __________________________________________________________________________

EXAMPLE 2

Utilizing the test procedure described above with respect to FIG. 1,aqueous treatment fluids were passed through Ohio Sandstone Cores todetermine the damaging effect of the fluid on the cores. The treatmentfluids consisted of water solutions of the formation control additivesof this invention present in the fluids in the amount of 0.5 percentadditive by total weight of fluid.

The test results, which are provided in Table II, include the chemicalidentity of the fluid additive, the general structure thereof, thepercent additive in the fluid by weight of fluid and the core damageexpressed in terms of final permeability as a percent of initialpermeability.

                  TABLE II                                                        ______________________________________                                        OHIO SANDSTONE CORE                                                                Chemical Compound General  %      K/K.sub.i,                             Test Name              Structure                                                                              Solution                                                                             %                                      ______________________________________                                        1    2-Hydroxy-N,N-Bis R.sub.1 DR.sub.1 Z                                                                     0.5    87.8                                        (2-Hydroxy Ethyl)-                                                                              R.sub.1                                                     N-Methyl                                                                      Ethanaminium Chloride                                                    2    N,N,N-Trimethyl   E Y      0.5    89.0                                        Methanaminium Acetate                                                    3    2-Hydroxy-N,N,N-Trimethyl                                                                       AR.sub.1 Z                                                                             0.5    90.5                                        Ethanaminium Citrate                                                     4    N-Methyl Alkyl    CR.sub.3 Z                                                                             0.5    92.6                                        Pyridinium Chloride                                                      5    2-Hydroxy-N,N,N-Trimethyl                                                                       AR.sub.1 Z                                                                             0.5    97.2                                        Ethanaminium Chloride                                                    6    2-Hydroxy-N,N,N-Tri-                                                                            AR.sub.1 Z                                                                             0.5    97.5                                        methyl-1 Propanaminium                                                        Acetate                                                                  7    1-Carboxy-N,N,N-Trimethyl                                                                       AR.sub.1 Z                                                                             0.5    97.5                                        Methanaminium Chloride                                                   8    1,3-Bis(Trimethanaminium),                                                                      AR.sub.2 A Z                                                                           0.5    98.3                                        2-Propanol Dichloride                                                    9    2-Hydroxy-N,N,N-Trimethyl                                                                       AR.sub.1 Z                                                                             0.5    99.5                                        Ethanaminium Acetate                                                     10   1,2-Bis(Trimethanaminium)                                                                       AR.sub.2 A Z                                                                           0.5    100.0                                       Ethane Dichloride                                                        11   2-Hydroxy-N-(2-Hydroxy                                                                          R.sub.1 BR.sub.1 Z                                                                     0.5    100.0                                       Ethyl)-N,N-Dimethyl                                                           Ethanaminium Chloride                                                    ______________________________________                                    

The results clearly illustrate the substantially nondamaging effect on aformation core sample upon exposure thereof to an aqueous fluidcontaining the formation stabilization additive of the presentinvention. The preferred embodiment of the present invention has beendescribed herein; however changes and modifications in the method andcompositions described can be made by one skilled in the art withoutdeparting from the spirit or scope of the invention as set forth in theappended claims.

What is claimed is:
 1. A method of treating a subterranean formationcomprising contacting said formation with an aqueous treatment fluidcontaining a formation control additive in an amount effective tostabilize said formation, said additive comprising a quaternary ammoniumcompound selected from compounds of the general formulas: ##STR15##wherein B represents the group ##STR16## D represents the group##STR17## and F represents ##STR18## and further wherein: R₁ is selectedfrom the groups --CH₂ COOH, --CH₂ CH₂ OH, --CH₂ CH₂ CH₂ OH and --CH₂CHOHCH₃ ;R₂ is selected from the groups --CH₂ CH₂ --, --CH₂ CHOHCH₂ --,--CH₂ CH₂ CH₂ --, --CH₂ CH₂ CH₂ CH₂ --, and --CH₂ CH₂ OCH₂ CH₂ --, and Zis an anion selected from halides, nitrates, nitrites, sulfites,sulfates and carboxylates.
 2. The method of claim 1 wherein saidformation control additive is present in said treatment fluid in anamount of about 0.05% by weight of said treatment fluid.
 3. The methodof claim 1 wherein said formation control additive is present in saidtreatment fluid in an amount of from about 0.1 to about 5% by weight ofsaid treatment fluid.
 4. The method of claim 3 wherein said treatmentfluid has a pH in the range of from about 1 to about
 11. 5. The methodof claim 4 wherein said quaternary ammonium compound is selected fromthe group consisting of: 2-Hydroxy-N,N-Bis(2-Hydroxy Ethyl)-N-MethylEthanaminium Chloride and 2-Hydroxy-N-(2-Hydroxy Ethyl)-N,N-DimethylEthanaminium Chloride.
 6. The method of claim 1 wherein said treatmentfluid includes a gelling agent.
 7. The method of claim 1 wherein saidquaternary ammonium compound is selected from compounds of said generalformula

    R.sub.1 BR.sub.1 Z.


8. The method of claim 7 wherein R₁ is selected from said groups --CH₂CH₂ OH and --CH₂ CHOHCH₃ and Z is selected from halides, nitrates andcarboxylates.
 9. A method of stimulating the production of hydrocarbonsfrom a clay-containing subterranean formation comprising contacting saidformation with an aqueous treatment fluid under conditions sufficient tocreate at least one fracture in said formation to thereby stimulate theproduction of hydrocarbons from said formation: wherein said aqueoustreatment fluid is comprised of an aqueous fluid and a formation controladditive present in said treatment fluid in an amount effective tostabilize said formation, said additive comprising a quaternary ammoniumcompound selected from compounds of the general formulas: ##STR19##wherein B represents the group ##STR20## D represents the group##STR21## and F represents ##STR22## and further wherein: R₁ is selectedfrom the groups --CH₂ COOH, --CH₂ CH₂ OH, --CH₂ CH₂ CH₂ OH and --CH₂CHOHCH₃ ;R₂ is selected from the groups --CH₂ CH₂ --, --CH₂ CHOHCH₂ --,--CH₂ CH₂ CH₂ --, --CH₂ CH₂ CH₂ CH₂ --, and --CH₂ CH₂ OCH₂ CH₂ --; and Zis an anion selected from halides, nitrates, nitrites, sulfites,sulfates and carboxylates.
 10. The method of claim 9 wherein saidformation control additive is present in said treatment fluid in anamount of about 0.05% by weight of said treatment fluid.
 11. The methodof claim 9 wherein said formation control additive is present in saidtreatment fluid in an amount of from about 0.1 to about 5% by weight ofsaid treatment fluid.
 12. The method of claim 9 wherein said treatmentfluid includes a gelling agent.
 13. The method of claim 9 wherein saidtreatment fluid has a pH in the range of from about 1 to about
 11. 14.The method of claim 13 wherein said quaternary ammonium compound isselected from the group consisting of: 2-Hydroxy-N,N-Bis(2-HydroxyEthyl)-N-Methyl Ethanaminium Chloride and 2-Hydroxy-N-(2-HydroxyEthyl)-N,N-Dimethyl Ethanaminium Chloride.
 15. The method of claim 9wherein said quaternary ammonium compound is selected from compounds ofsaid general formula

    R.sub.1 BR.sub.1 Z.


16. The method of claim 15 wherein R₁ is selected from said groups --CH₂CH₂ OH and --CH₂ CHOHCH₃ and Z is selected from halides, nitrates andcarboxylates.